TW202221154A - Producing method of pd-adsorbed zno nanostructures - Google Patents

Abstract

The present invention reveals a producing method of Pd-adsorbed ZnO nanostructures comprising: preparing an ITO substrate which comprising a plurality of Zinc oxide (ZnO) nanostructures; using a photochemical reaction method to adsorb a number of palladium (Pd) nanoparticles on the surface of ZnO nanostructures. Compare to the traditional away, such as E-beam Evaporator system or Thermal Evaporation Deposition system, the present invention by using a photochemical reaction method not only achieves the effects with simplifying the producing steps, down costing the price, but also improves the development of the field emission.

Description

Process method for adsorbing palladium-zinc oxide nanocolumns

A kind of zinc oxide nano-column for field emitter, especially a kind of zinc oxide nano-column for adsorbing palladium and photochemical method thereof

The application of field emission is closely related to modern life, including flat panel displays for people's lives and electron beam microscopes for medical and research fields, etc., which makes the application of field emission in displays and electronic equipment in recent years. Extensive research. The current field emitters are mostly fabricated by growing a plurality of nanostructures (such as nanopillars or nanotubes) on an indium tin oxide substrate. However, the advantages and disadvantages of the field emitters can be attributed to many Factors include the nanostructure, nanomaterial, conductivity, work function, etc. of the field emitter. Therefore, how to improve the quality and performance of the field emitter is the most important goal in the field emission field.

In order to improve the quality and performance of the field emitter, metal oxide semiconductor (MOS) is often used as the target of development. Among them, zinc oxide has a 1. wide energy gap (3.37 eV) at room temperature, which is relatively high. Good isoelectricity; 2. High electron binding energy (60 meV) makes it have excellent luminescence and nonlinear optical coefficient characteristics; 3. Its chemical stability is not toxic and the material is cheap, making zinc oxide a field emission field A very popular nano research material in .

In addition, in the research field of metal oxide semiconductors and field emitters, a metal oxide semiconductor is doped with a noble metal nanoparticle (such as platinum, palladium, gold and silver, etc.) for oxide semiconductor modification. Thereby the performance of the field emitter is improved. However, in the current technology, an electron beam evaporation system or a thermal evaporation system is mostly required to sputter the precious metal nanoparticles on the surface of the metal oxide semiconductor, which is not only expensive and complicated, but also unfavorable for the field emission field. develop.

In order to solve the technical field of improving the quality and performance of the field emitter in the current field emission field, the manufacturing cost and process steps can be reduced. The manufacturing method of the zinc oxide nano-columns comprises the following steps: preparing an indium tin oxide substrate on which a plurality of oxide nano-columns are grown; and utilizing a photochemical reaction to make a plurality of the zinc oxide nano-columns A plurality of palladium nanoparticles are adsorbed on the surface of the rice pillar.

Wherein, the step of the photochemical reaction comprises: dropping an aqueous solution of palladium chloride onto a plurality of the zinc oxide nanopillars; and exposing the plurality of the zinc oxide nanopillars with the aqueous palladium chloride solution to an ultraviolet ray light source.

Wherein, a sputtering method is used to form a zinc oxide film on the indium tin oxide substrate, and the sputtering method includes a radio frequency magnetron sputtering system.

Wherein, the thickness of the zinc oxide film is between 25 nanometers (nm) and 100 nanometers (nm).

Wherein, using a hydrothermal method to grow a plurality of the zinc oxide nano-columns, the steps of the hot water method include: immersing the indium tin oxide substrate in a mixture of zinc nitrate hexahydrate and a molar concentration ratio of 1:1. cyclohexamethylenetetramine solution; and react at 90°C for 6 hours.

Wherein, the volume of this palladium chloride aqueous solution is 500 microliters, and this palladium chloride aqueous solution concentration is 1 homole per liter.

Wherein, the wavelength of the ultraviolet light source is 365 nm, the intensity of the ultraviolet light source is 0.496 mW, and the duration of exposing the plurality of zinc oxide nanocolumns to the ultraviolet light source is 480 seconds.

Further, the indium tin oxide substrate is plated with a silver layer as a contact electrode.

Compared with the zinc oxide nanocolumns, when the same electric field is applied to the zinc oxide nanocolumns for adsorbing palladium, the field emission performance of the zinc oxide nanocolumns for adsorbing palladium is obviously better than that of the zinc oxide nanocolumns .

Compared with the traditional electron beam evaporation system or thermal evaporation system, the palladium nanoparticles can be sputtered on the surface of the zinc oxide nanocolumns, the present invention utilizes the photochemical reaction to make the palladium ions from the solution. The adsorption on the surface of the zinc oxide nanopillars 13 is not only simple in steps and cheap, but also beneficial to the development of the field emission field.

As shown in FIG. 1, it is a process method for ZnO nanocolumns 10 for adsorbing palladium provided by a preferred embodiment of the present invention. The steps include: 1. preparing and cleaning an indium tin oxide substrate 11, the indium tin oxide The bottom of the object substrate 11 is a glass plate, the glass plate is coated with an indium tin oxide film, and the indium tin oxide substrate 11 is cleaned with acetone, methanol, deionized water and an ultrasonic oscillator. 2. Using a RF magnetron sputtering system, in a vacuum environment (4*10 ^-6 Torr), sputter 3-inch diameter zinc oxide nanoparticles on the indium tin oxide A zinc oxide film 12 is formed on the upper layer of the object substrate 11 , and the thickness of the zinc oxide film 12 is about 25 nanometers (nm) to 100 nanometers (nm). 3. Using a hydrothermal method to grow into a plurality of zinc oxide nanopillars 13. 4. Using a photochemical reaction, a plurality of palladium nanoparticles 14 are adsorbed on the surfaces of the plurality of zinc oxide nanopillars 13 5. In a vacuum environment (6*10 ^-6 Torr), the indium tin oxide substrate 11 is coated with a silver layer 15 as a contact electrode, and the thickness of the silver layer 15 is about 100 nanometers (nm) .

The steps and conditions of the hot water method include: 1. immersing the indium tin oxide substrate 11 coated with the zinc oxide layer 12 in zinc nitrate hexahydrate ( Zn(NO3)2_6H2O) and hexamethylenetetramine (hexamethylenetetramine, C6H12N4, HMTA) solution. 2. A plurality of zinc oxide nanopillars 13 are grown into a plurality of zinc oxide nanopillars by reacting at 90° C. for 6 hours.

Wherein the steps and conditions of this photochemical reaction include: 1. 500 microliters (μL) of palladium monochloride (PdCl ) aqueous solution 20 is dropped onto a plurality of the zinc oxide nanopillars 13, the palladium chloride aqueous solution is preferably The concentration is 1 hamol (1 mM) per liter. 2. Expose a plurality of this zinc oxide nano-columns 13 with this palladium chloride aqueous solution 20 to an ultraviolet light source 30, in this embodiment, the wavelength of this ultraviolet light source 30 is 365 nanometers (nm) and the intensity is 0.496 millimetres Watts (mW), the duration of exposing the plurality of the zinc oxide nanocolumns 13 to the one ultraviolet light source 30 is 480 seconds. When the zinc oxide nano-columns 13 react with the palladium chloride aqueous solution 20, a plurality of palladium ions (Pd ²⁺ ) in the palladium chloride aqueous solution 20 will react with a plurality of oxygen atoms of the zinc oxide nano-columns 13, And adsorbed on the surface of the zinc oxide nano-columns 13, through the irradiation of the ultraviolet light source 30, a plurality of the palladium ions are reduced to a plurality of the palladium nanoparticles 14 through a photochemical reaction, and the plurality of the palladium nanoparticles 14 are formed on the surfaces of the plurality of zinc oxide nanopillars 13 .

Compared with the traditional electron beam evaporation system or thermal evaporation system, the palladium nano-particles 14 can be sputtered on the surface of the zinc oxide nano-columns 13. The present invention uses the photochemical reaction to make the palladium ions. Adsorption on the surface of the zinc oxide nano-pillars 13 from solution is not only simple in steps and cheap, but also beneficial to the development of the field emission field.

The present invention will further compare the differences between the plurality of zinc oxide nanocolumns 13 and the plurality of zinc oxide nanocolumns 10 for adsorbing palladium. FIG. 2 is an electrophotographic diagram of a preferred embodiment of the present invention, which is a photograph of a plurality of the zinc oxide nano-columns 13 and a plurality of the palladium-adsorbing zinc oxide nano-columns 10 after growth. The left rows (a) and (b) are respectively a top view of a plurality of the zinc oxide nanocolumns 13 and a plurality of the palladium-adsorbing zinc oxide nanocolumns 10; the right rows (c) and (d) are respectively a plurality of the A side view of the zinc oxide nanocolumns 13 and a plurality of the zinc oxide nanocolumns 10 for adsorbing palladium. After measurement, the average diameters of the plurality of zinc oxide nano-columns 13 and the plurality of the palladium-adsorbed zinc oxide nano-columns 10 are about 83 and 86 nanometers (nm), respectively, and the average lengths are about 2.11 and 2.14 microns ( µm). It can be seen from the top views (a) and (b) that the plurality of the zinc oxide nano-columns 13 and the plurality of the palladium-adsorbing zinc oxide nano-columns 10 are columns of a hexagonal structure. Among them, from the enlarged view (e) of the upper right corner of the figure (b), it can be observed that the surface of the zinc oxide nanocolumns 10 adsorbing palladium is slightly rough, and it can be known that there are a plurality of the palladium nanoparticles 14 adsorbed on a plurality of the The surface of the zinc oxide nanocolumns 10 for adsorbing palladium.

3 is an analysis diagram of an X-ray diffractometer according to a preferred embodiment of the present invention. The X-ray diffractometer is used to detect the characteristics of crystal materials, including analysis of structural parameters such as structure, phase and crystal orientation. The X-ray diffraction peak quality is produced by the constructive interference of monochromatic light diffracted at specific angles from the lattice planes of each set of samples, and the intensity of the peak is determined by the distribution of atoms within the lattice. It can be seen from the card number 36-1451 in the Joint Committee on Powder Diffraction Standards (JCPDS) database that zinc oxide is a heterogeneously grown hexagonal wurtzite structure, and the obvious (002) peak can indicate that The plurality of the zinc oxide nano-columns 13 and the plurality of the palladium-adsorbing zinc oxide nano-columns 10 preferentially grow rapidly in the c-axis direction, and no other diffraction peaks are found, which indicates that no impurities exist.

4 is an analysis diagram of a photoluminescence spectrometer according to a preferred embodiment of the present invention. It can be seen from the figure that there is a main peak, and the main peak falls at 380 nm, wherein the peak at 380 nm can correspond to the zinc oxide nanocolumn 13 And the near-band edge emission (near-band edge emission) and the free excitonic recombination of the zinc oxide nanocolumns 10 adsorbing palladium, wherein the zinc oxide nanocolumns 10 adsorbing palladium are directed toward The lower peak intensity for the ZnO nanopillars 13 may be due to photo-excited electrons to move from ZnO to the palladium nanoparticles in the conduction band, resulting in reduced electron-hole recombination in ZnO , while the separated phase of photoinduced electrons and holes increases, and the resulting photoluminescence intensity decreases.

FIG. 5 is a field emission result diagram of a preferred embodiment of the present invention. As shown in the figure, when the current density is 10 ⁻⁵ ampere/cm ² (A/cm ² ), the open electric field value of the zinc oxide nanocolumns 13 is 6.68 volt/micrometer (V/μm), however, the turn-on electric field value of the palladium-adsorbed zinc oxide nanopillars 10 drops to 6.43 volts/micron (V/μm), because the palladium-adsorbed zinc oxide nanopillars 10 provide more carriers, making it easier for electrons to tunnel. According to the tunneling current FN formula, it can be known that the field enhancement factor (β) value will increase when the turn-on electric field strength decreases, and the enhancement factor can usually be used as the basis for judging the quality of the element. Therefore, it can be known from the data that the adsorption of palladium The zinc oxide nanopillar 10 is more suitable as a field emission element.

FIG. 6 is a field emission slope diagram of a preferred embodiment of the present invention. According to the tunneling current FN formula, a field emission slope diagram of ln(J/E ² ) and 1/E is further obtained. The zinc oxide nanopillars 13 and the The field emission slopes of the ZnO nanocolumns 10 adsorbing palladium are 31.48 and 14.01, respectively. When a 5.3 electron volt (eV) is given to the ZnO material, the ZnO nanocolumns 13 and the ZnO nanocolumns adsorbing palladium are The field emission enhancement factor (β) values of Mi-pillar 10 are 2546.69 and 5947.07, respectively. From the results, it can be seen that the ZnO nanopillars 10 adsorbing palladium significantly increase the enhancement factor (β) value and show better field emission performance. .

As shown in FIG. 7 , it is a schematic diagram of the field emission energy band measured by an applied electric field in a preferred embodiment of the present invention. FIG. 7( a ) is a schematic diagram of the field emission energy band of the zinc oxide nanocolumn 13 . After an electric field is applied to the nanopillars 13, when the electron e- gains energy ^from a valence band and jumps across an energy gap (Eg) to the conduction band, the conduction of the zinc oxide nanopillars 13 The conduction band is bent to the Fermi level, creating a quantum well in which electrons e- can be stored and tunneled ^to the vacuum level ) produces a current. However, as shown in FIG. 7( a ), when the same electric field is applied to the ZnO nanocolumns 10 adsorbing palladium, the field emission performance of the ZnO nanocolumns 10 adsorbing palladium is significantly better than that of the ZnO nanocolumns M column 13, the reasons can be summarized as follows: 1. Since the noble metal palladium can adsorb more electrons e ^- , the overall conductivity is enhanced. 2. The heterostructure of the zinc oxide nanocolumns 10 for adsorbing palladium further increases the storage capacity of the quantum well, so that more electrons e- can be gathered in the quantum well ⁱⁿ large quantities, ^The number of electrons e- that tunnels to the vacuum level increases, and the transfer of current is relatively improved.

10: ZnO nanopillars adsorbing palladium 11: Indium tin oxide substrate 12: Zinc oxide film 13: ZnO nanopillars 14: Palladium nanoparticles 15: Silver layer 20: Palladium chloride aqueous solution 30: Ultraviolet light source e : ^-Electronics

Fig. 1 is a step diagram of a preferred embodiment of the present invention Fig. 2 is the electrograph of the preferred embodiment of the present invention Fig. 3 is the X-ray diffractometer analysis diagram of the preferred embodiment of the present invention FIG. 4 is an analysis diagram of a photoluminescence spectrometer according to a preferred embodiment of the present invention. FIG. 5 is a diagram of the field emission result of the preferred embodiment of the present invention FIG. 6 is a field emission slope diagram of a preferred embodiment of the present invention FIG. 7 is a schematic diagram of measuring the field emission energy band with an applied electric field according to a preferred embodiment of the present invention.

10: ZnO nanocolumns for adsorption of palladium

11: Indium Tin Oxide Substrate

12: Zinc oxide film

13: Zinc oxide nanopillars

14: Palladium Nanoparticles

15: Silver Layer

20: palladium chloride aqueous solution

30: UV light source

Claims (9)

A process method for adsorbing palladium zinc oxide nano-pillars, the steps comprising: preparing an indium tin oxide substrate with a plurality of oxide nano-pillars growing on the indium tin oxide substrate; and Utilize a photochemical reaction to make a plurality of palladium nanoparticles adsorbed on the surfaces of the plurality of zinc oxide nanopillars, and the steps of the photochemical reaction include: dropping an aqueous solution of palladium monochloride onto a plurality of the zinc oxide nanopillars; and A plurality of the zinc oxide nanocolumns with the aqueous palladium chloride solution dripped thereon are exposed to an ultraviolet light source. As claimed in claim 1, for the method for manufacturing ZnO nanocolumns for adsorbing palladium, a ZnO film is formed on the indium tin oxide substrate by a sputtering method, and the sputtering method includes a radio frequency magnetron sputtering. system. According to the manufacturing method of the zinc oxide nanocolumns for adsorbing palladium according to claim 1 or 2, the thickness of the zinc oxide film is between 25 nanometers (nm) and 100 nanometers (nm). As claimed in claim 1 or 2, the process method for absorbing palladium zinc oxide nanocolumns utilizes a hydrothermal method to grow a plurality of the zinc oxide nanocolumns, and the steps of the hydrothermal method comprise: immersing the indium tin oxide substrate in a solution of zinc nitrate hexahydrate and cyclohexamethylenetetramine mixed in a molar concentration ratio of 1:1; and The reaction was carried out at 90°C for 6 hours. As claimed in claim 1 or 2, the process method of the zinc oxide nanocolumn for adsorbing palladium, the volume of the palladium chloride aqueous solution is 500 microliters, and the concentration of the palladium chloride aqueous solution is 1 homole per liter. As claimed in claim 1 or 2, the method for manufacturing ZnO nanocolumns for adsorbing palladium, the wavelength of the ultraviolet light source is 365 nm, the intensity of the ultraviolet light source is 0.496 mW, and a plurality of the zinc oxide nanocolumns are exposed to the The duration of a UV light source was 480 seconds. The method for manufacturing ZnO nanocolumns for adsorbing palladium according to claim 5, the wavelength of the ultraviolet light source is 365 nm, the intensity of the ultraviolet light source is 0.496 mW, and a plurality of the zinc oxide nanocolumns are exposed to the one ultraviolet light The duration of the light source is 480 seconds. As claimed in claim 1 or 2, for the manufacturing method of palladium-adsorbing zinc oxide nanopillars, the indium tin oxide substrate is coated with a silver layer as a contact electrode. According to the manufacturing method of the zinc oxide nano-columns for adsorbing palladium as described in claim 7, the indium tin oxide substrate is coated with a silver layer as a contact electrode.

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